NAME

ClassEncapsulatedAttributes - A set of example metaclasses with class encapsulated attributes

SYNOPSIS

            

              
              
package Foo;
use metaclass 'ClassEncapsulatedAttributes';
Foo->meta->add_attribute('foo' => (
    accessor  => 'Foo_foo',
    default   => 'init in FOO'
));
sub new  {
    my $class = shift;
    $class->meta->new_object(@_);
}
package Bar;
our @ISA = ('Foo');
# duplicate the attribute name here
Bar->meta->add_attribute('foo' => (
    accessor  => 'Bar_foo',
    default   => 'init in BAR'            
));      
# ... later in other code ...
my $bar = Bar->new();
prints $bar->Bar_foo(); # init in BAR
prints $bar->Foo_foo(); # init in FOO  
# and ...
my $bar = Bar->new(
    'Foo' => { 'foo' => 'Foo::foo' },
    'Bar' => { 'foo' => 'Bar::foo' }        
);  
prints $bar->Bar_foo(); # Foo::foo
prints $bar->Foo_foo(); # Bar::foo
            
          

DESCRIPTION

This is an example metaclass which encapsulates a class's attributes on a per-class basis. This means that there is no possibility of name clashes with inherited attributes. This is similar to how C++ handles its data members.

ACKNOWLEDGEMENTS

Thanks to Yuval "nothingmuch" Kogman for the idea for this example.

AUTHORS

Stevan Little <stevan@iinteractive.com>

Yuval Kogman <nothingmuch@woobling.com>

COPYRIGHT AND LICENSE

Copyright 2006-2008 by Infinity Interactive, Inc.

http://www.iinteractive.com

This library is free software; you can redistribute it and/or modify it under the same terms as Perl itself.